Thumbnail Image Resizer

I don’t understand how the image resizer could be made so confusing to work with.

I have a bunch of images uploaded. I want to set one as a featured image but I don’t like how the crop on the thumbnail is.

1. I click on Add Featured Image.
2. I select an image.
3. I click on edit image
4. I resize to correct dimension
5. I select apply changes to Thumbnail.
6. I click back….nothing happens.
7. I click scale and it changes the original image so I don’t have a full size image for any zoom features.

How do I change just the thumbnail size? I realize there are plugins that can help with this. Usually if I bang on it long enough I can get it figured out. The problem is I have clients that I have to show how to do this and half the time I don’t know exactly how to do it….how can I expect them to understand. AND I can’t find any plugins that have fixed this.

This is the number 1 thing I HATE about wordpress. Someone really needs to make this image editor more intuitive. Or at least post some documentation.